CJK Fonts, Character Sets & Encodings. All CJK. #AllOfTheTime.

HKSCS-2016 & Adobe-CNS1-7

Unlike Unicode, which has been on an annual release cycle from Version 7.0, mainly to provide predictability to the release schedule for the benefit of developers, national standards—particularly East Asian ones—are updated much less frequently.

The latest East Asian national standard to be updated is HKSCS (Hong Kong Supplementary Character Set). HKSCS-2016, the fifth version of this particular standard, was published in May of 2017. As a result, and for the benefit of font developers whose fonts are based on Adobe’s public glyph sets, I used the morning of 🇺🇸’s Fourth of July of this year to publish Adobe-CNS1-7 via the CMap Resources open source project.
What changed? HKSCS-2016 added 24 characters and changed the mappings for two characters. 22 of the 24 new characters are encoded variants of existing Big Five characters whose representative glyphs are considered the preferred form in Hong Kong. The image below shows 22 character pairs whereby the one on the left is the one that is preferred in Hong Kong:

The two additional characters are U+9C47 鱇 and U+20AC €.

The two changed mappings affect U+3D1D 㴝 and U+4CA4 䲤 in Extension A, which now map to U+2A3ED 𪏭 (Extension B) and U+9FD0 鿐 (Unicode Version 8.0), respectively.

All of the above resulted in a modest 23 additional glyphs for Adobe-CNS1-7, along with 25 additional mappings for its Unicode CMap resources. Adobe-CNS1-3 already included glyphs for U+20AC €, which left 23 glyphs that are assigned to CIDs 19156 through 19178. The 25 additional mappings are for the 23 new glyphs plus those for U+9FD0 鿐 and U+2A3ED 𪏭, which are double-mapped from U+4CA4 䲤 and U+3D1D 㴝, respectively.

2017-10-10 Update: In lieu of updating Adobe Tech Note #5080, I decided to move the specification to GitHub. See the Adobe-CNS1 project for the Adobe-CNS1-7 glyph table. In addition to adding Supplement 7 material, the text proper was ported to GitHub markdown syntax.